Description:
------------
Overriding constants defined in interfaces isn't allowed in classes that implement the interface, but is in classes that extend classes that implement the interface.

Test script:
---------------
<?php

interface FooInterface
{
    const BAR = '';
}

class Foo implements FooInterface
{
    const BAR = 'BAR';
}

$baz = new Foo;

var_dump($baz::BAR);

https://3v4l.org/qVreY


<?php

interface FooInterface
{
    const BAR = '';
}

abstract class AbstractFoo implements FooInterface
{
    
}

class Foo extends AbstractFoo
{
    const BAR = 'BAR';
}

$baz = new Foo;

var_dump($baz::BAR);

https://3v4l.org/9S53j

Expected result:
----------------
Either both cases work or both result in the error "Fatal error: Cannot inherit previously-inherited or override constant SOME_CONST from interface MyInterface".

Actual result:
--------------
The first case gives the error "Fatal error: Cannot inherit previously-inherited or override constant SOME_CONST from interface MyInterface".

The second case works normally.